Netori, MC is the one doing the blackmailing.

Base +19, psyburn21 +19, babasr -13, nooby0112 -7, akunoko -28

Yup, big-tittied schoolgirl, blackmail sex, boyfriend standing on the other side of the lockers when she's getting boned NTR, damned good stuff.........love this artist, their themes and art are great, I'm thinking this is the first thing they've done with original characters, super nice to see, thanks a lot for sharing :)

Base +35, psyburn21 +19, Colonia +6, nooby0112 -7, akunoko -28

https://www.doujinshi.org/book/995404/

Base +50, Ooe Kintarou +10, psyburn21 +19, hondawhr -24, nooby0112 -7

Based on the title it's not simple blackmail, but some sort of government program pairing up genetically compatible people to fight the lowering birth rate that japan suffers from. The Netori guy and the heroine have been matched up and he's taking full advantage, probably saying that she has to do it with him or break the law. She really doesn't want to, but doesn't want her beloved sweetheart to know she's been matched with another man. So she agrees to do it secretly. "I'll do what you tell me, so please don't let him know."
Pretty much an "only in hentai" plot. No matter how submissive to authority the Japanese are, even they would never go along with something like that.

Base +6, Ooe Kintarou +10, Slobber +30, psyburn21 +19, Colonia +6, Gitami +12, Daddyfatsack +6, davivico +6, Lostalgia +7, nooby0112 -7, Crusader95 +2, akunoko -28

damn, can a bro help me out? this reminds me of that doujin where an oji-san is assigned to help teach younger couples how to have sex because of lowering birth rate meme, and he fucks the girlfriend in front of the MC until MC gets hard and fucks her himself. the last page is good guy oji-san leaving to spread his knowledge elsewhere, anyone remember what it's called?

Base +7, bergil -6, nooby0112 -7, akunoko -28

@Summergraffiti, Sounds like Total Inseminator ♂ Contractor Nobuo Aragaki by Miito Shido.

Link to English: /g/1025339/e0978d23aa/

Base +5, bergil -6, nooby0112 -7